Dietary Fats

Dietary Fats

Fats are the most energy-dense of the three
macronutrients. Fats are made up of the same elements as carbohydrates -
carbon, hydrogen, oxygen - but the way the atoms are linked together is
different. (oils, are simply fats that are liquid rather than solid at
room temperature) Fats, which can be found in both plants and animals,
are insoluble in water. They are grouped in three categories: simple
fats (triglycerides), compound fats (phospholipids, glucolipids,
lipoproteins), and derived fats (cholesterol).

Fats in the body serve three basic
functions:

1) Provide the major source of stored
energy (body fat)

2) Serve to cushion and protect the
major organs

3) Act as an insulator, preserving body
heat and protecting against excessive cold.

Fat is the most calorie-dense of any
nutrient. A pound of fat contains about 4000 calories, as opposed to
1800 calories stored in a pound of protein or carbohydrate.

When you exercise, assuming you stay
within your aerobic capacity (don't get out of breath), the body uses
fats and carbohydrates for energy on about a 50-50 basis. But the longer
you continue steady exercise, the higher the percentage of fat used.
After working three hours or so, the body may derive as much as 80
percent of its energy from fat.